Has it ever been stated in the films what year it is ?
I assume the films aren't set in the 1990s, like the books, because the movies make use of the Millenium Bridge and the Gherkin Building as settings, which weren't built until 2000 and 2004 respectively.
I have dones some research and have come up with a possible timeline that fits the movies quite nicely.
EG :
Summer 2004 - Unpredictable Weather. From extreme heat to thunderstorms, as shown in OOTP.
Millenium Bridge and Gherkin - as mentioned above, used in HBP.
No indication of the year has been given on close-ups of the Daily Prophet, as the font is too small to read. There are more reasons, but don't have time to go through them all now. Here's the Harry Potter Movie Timeline, based on info collected from the films :
1881
1882
1883 ----- Dumbledore’s Birth
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936---- December 31 - Voldemort’s birth
1937--- Memory vial of Tom Riddle (Sr.), belonging to someone else
1938 ------ Dumbledore’s Memory vial of Tom Riddle (Sr.) - belonging to someone else
----- Hagrid’s Birth
1939
1940
1941
1942
1943
1944
1945 ------- Dumbledore’s Defeat of Grindelwald, both 63, Summer 1945
1946
1947
1948 -------- Tom Riddle’s First attendance, September 1st 1947 (he’d be 12 on 31st December)
1949
1950 ------- Hagrid’s First Attendance (he’d be 12 on 6th December)
1951
1952 ------ Chamber of Secrets First Opening , 15 yrs old (Year 5). 16 in December
1953------- Tom Riddle knows about Horcruxes from Prof. Slughorn. 16yrs old (17 in December)
1954
1955 ------- Tom Riddle’s Hogwarts leaving date, aged 18.
------- Sirius, James, Lily, Lupin, Pettigrew & Snape born
1956
1957 -------- Hagrid’s Hogwarts Leaving Date
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971 ---------- Lord Voldemort asks Dumbledore for DADA job in November.
1980------ Lord Voldemort’s First Full rise to power
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990 ------- Harry Potter was born James and Lily Potter : 35 years old
1991---- Oct 31. Lord Voldemort’s Downfall. 54 years old (55 in December)
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
--------- PS
2002
------- COS
2003
------- POA
2004
-------- GOF
2005-------- Summer 2005 - Lord Voldemort’s Return - aged 68
------ OOTP
2006
----- HBP
2007------- Summer 2007 - Dumbledore’s Death - aged 123
------ DH
2008 --------- March 2008 - Lord Voldemort’s Defeat - aged 71 (72 in December)
The car used in the flashback of Dumbledore walking to Wools Orphanage in HBP, could possibly be made in 1947, as that design looks very similar. The way in which people were dressed also seemed as if they were from the 40s (top hat, old-fashioned bike..)
Ciaran Hinds said in an interview that movie-Dumbledore was 'around 123'.
I must say that I didn't create all of this timeline.